The create_hyp_mappings() function can currently be called at any point
in time. However, its behaviour in protected mode changes widely
depending on when it is being called. Prior to KVM init, it is used to
create the temporary page-table used to bring-up the hypervisor, and
later on it is transparently turned into a 'share' hypercall when the
kernel has lost control over the hypervisor stage-1. In order to prepare
the ground for also unsharing pages with the hypervisor during guest
teardown, introduce a kvm_share_hyp() function to make it clear in which
places a share hypercall should be expected, as we will soon need a
matching unshare hypercall in all those places.
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-7-qperret@google.com
#include <asm/kvm_pgtable.h>
#include <asm/stage2_pgtable.h>
+int kvm_share_hyp(void *from, void *to);
int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot);
int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size,
void __iomem **kaddr,
if (ret)
return ret;
- ret = create_hyp_mappings(kvm, kvm + 1, PAGE_HYP);
+ ret = kvm_share_hyp(kvm, kvm + 1);
if (ret)
goto out_free_stage2_pgd;
if (err)
return err;
- return create_hyp_mappings(vcpu, vcpu + 1, PAGE_HYP);
+ return kvm_share_hyp(vcpu, vcpu + 1);
}
void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
struct user_fpsimd_state *fpsimd = ¤t->thread.uw.fpsimd_state;
/* Make sure the host task fpsimd state is visible to hyp: */
- ret = create_hyp_mappings(fpsimd, fpsimd + 1, PAGE_HYP);
+ ret = kvm_share_hyp(fpsimd, fpsimd + 1);
if (!ret)
vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
return 0;
}
+int kvm_share_hyp(void *from, void *to)
+{
+ if (is_kernel_in_hyp_mode())
+ return 0;
+
+ /*
+ * The share hcall maps things in the 'fixed-offset' region of the hyp
+ * VA space, so we can only share physically contiguous data-structures
+ * for now.
+ */
+ if (is_vmalloc_or_module_addr(from) || is_vmalloc_or_module_addr(to))
+ return -EINVAL;
+
+ if (kvm_host_owns_hyp_mappings())
+ return create_hyp_mappings(from, to, PAGE_HYP);
+
+ return pkvm_share_hyp(__pa(from), __pa(to));
+}
+
/**
* create_hyp_mappings - duplicate a kernel virtual address range in Hyp mode
* @from: The virtual kernel start address of the range
if (is_kernel_in_hyp_mode())
return 0;
- if (!kvm_host_owns_hyp_mappings()) {
- if (WARN_ON(prot != PAGE_HYP))
- return -EPERM;
- return pkvm_share_hyp(kvm_kaddr_to_phys(from),
- kvm_kaddr_to_phys(to));
- }
+ if (!kvm_host_owns_hyp_mappings())
+ return -EPERM;
start = start & PAGE_MASK;
end = PAGE_ALIGN(end);
if (!buf)
return -ENOMEM;
- ret = create_hyp_mappings(buf, buf + reg_sz, PAGE_HYP);
+ ret = kvm_share_hyp(buf, buf + reg_sz);
if (ret) {
kfree(buf);
return ret;